A novel 3DCT-based classification for posterior cruciate ligament tibial avulsion fractures

The Meyers and McKeever (MM) classification is widely used for posterior cruciate ligament (PCL) tibial avulsion fractures; however, it fails to comprehensively reflect fracture characteristics and morphology due to its exclusive reliance on plain radiographs, which may result in suboptimal treatment decisions. Computed tomography (CT) scanning and three-dimensional computed tomography (3DCT) reconstruction can provide a more detailed visualization of articular fracture configurations, enabling the development of effective treatment strategies. Therefore, we developed a novel classification system for PCL tibial avulsion fractures based on fracture characteristics on 3DCT images, systematically evaluated and compared classification accuracy and reliability with the MM classification.

Patients aged 18 years or older who underwent plain radiographs and CT examinations that confirmed PCL tibial avulsion fractures from June 2020 to Jan 2025 were included. A novel 3DCT-based classification system was established by considering three key fracture characteristics: fracture displacement degree, fracture line numbers, and fracture involvement regions. To verify the reliability and accuracy of the novel 3DCT-based and MM classification systems, intra- and inter-rater reliability assessments were performed. Additionally, the consistency and discrepancy in fracture patterns between the two classification systems were systematically described.

Ultimately, 53 patients (40 males and 13 females) with PCL tibial avulsion fractures were enrolled in the final study (mean age 42.9, range 22-65). The novel 3DCT-based classification system consisted of four principles and seven categories. The intra-rater reliability of the MM classification demonstrated substantial agreement, whereas the 3DCT-based classification exhibited perfect agreement. The inter-rater reliability of both classifications displayed substantial agreement, and the novel classification had higher reliability values. In addition, approximately 22.6% of non-displaced fracture types, along with some type II and III fractures identified through radiographs, exhibited differing fracture characteristics when evaluated using 3DCT.

The novel 3DCT-based classification is more reliable, simplified, and intuitive than the MM classification. This novel classification system allows for a more accurate description of these fractures and reduces the risk of misdiagnosis based on radiographs. Additionally, it provides valuable guidance for preoperative planning and the selection of appropriate treatment strategies.